Linux is an operating system and can be installaed on any personal computer

Then Linux is an alternative to Windows e MacOS.

Linux is an open system, not proprietary, supported by a wide community, it is immune to the ordinary viruses and last not least it is free of charge. You can find it as a "distribution" which takes the name from the organization that makes the packaging (e.g. Fedora, Ubuntu, Suse etc...).

To give an idea by using Linux you don't need neither to buy an antivirus nor to make the expensive cleaning of the personal computer, typical in the Windows environment, to solve the performace degradation that occurs over time.

Now, the Linux installation is not commercially supported by the hardware manufacturers yet, although there start to be a few exceptions.